diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index 1d0ae22..69efc82 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -16,7 +16,8 @@ jobs:
     - name: Set up Java
       uses: actions/setup-java@v1
       with:
-        java-version: 11
+        java-version: '21'
+        distribution: 'temurin'
     - name: Gradle cache
       uses: actions/cache@v2
       with:
diff --git a/README.md b/README.md
index 16454e3..7406410 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,8 @@
 ![CI](https://github.com/rogervinas/spring-cloud-stream-kafka-step-by-step/actions/workflows/gradle.yml/badge.svg)
-![Java](https://img.shields.io/badge/Java-11-blue?labelColor=black)
-![Kotlin](https://img.shields.io/badge/Kotlin-1.6.10-blue?labelColor=black)
-![SpringBoot](https://img.shields.io/badge/SpringBoot-2.6.2-blue?labelColor=black)
-![SpringCloudStream](https://img.shields.io/badge/SpringCloudStream-3.2.1-blue?labelColor=black)
+![Java](https://img.shields.io/badge/Java-21-blue?labelColor=black)
+![Kotlin](https://img.shields.io/badge/Kotlin-1.9.20-blue?labelColor=black)
+![SpringBoot](https://img.shields.io/badge/SpringBoot-3.1.5-blue?labelColor=black)
+![SpringCloudStream](https://img.shields.io/badge/SpringCloudStream-4.0.4-blue?labelColor=black)
 
 # Spring Cloud Stream & Kafka binder step by step
 
@@ -43,10 +43,10 @@ Our final goal is to produce messages to a Kafka topic.
 
 From the point of view of the application we want an interface `MyEventProducer` to produce events to a generic messaging system. These events will be of type `MyEvent`, just containing a `text` field to make it simpler:
 ```kotlin
-class MyEvent(val text: String)
+data class MyEvent(val text: String)
 
-interface MyEventProducer {
-    fun produce(event: MyEvent)
+interface MyEventProducer { 
+  fun produce(event: MyEvent)
 }
 ```
 
@@ -73,7 +73,7 @@ spring:
 ### 2) We create an implementation of `MyEventProducer` as a `Supplier` of `Flux<MyEventPayload>`, to fulfill the interfaces that both our application and Spring Cloud Stream are expecting:
 ```kotlin
 class MyStreamEventProducer : Supplier<Flux<MyEventPayload>>, MyEventProducer {
-  val sink = Sinks.many().unicast().onBackpressureBuffer<MyEventPayload>()
+  private val sink = Sinks.many().unicast().onBackpressureBuffer<MyEventPayload>()
 
   override fun produce(event: MyEvent) {
     sink.emitNext(toPayload(event), FAIL_FAST)
@@ -88,25 +88,30 @@ class MyStreamEventProducer : Supplier<Flux<MyEventPayload>>, MyEventProducer {
   }
 }
 
-class MyEventPayload @JsonCreator constructor(
-  @JsonProperty("string") val string: String,
-  @JsonProperty("number") val number: Int
+data class MyEventPayload(
+  val string: String,
+  val number: Int
 )
 ```
-* We use a DTO `MyEventPayload` to specify how do we want the payload to be serialized to JSON (using [Jackson](https://github.com/FasterXML/jackson) annotations).
+* We use a DTO `MyEventPayload` to specify how do we want the payload to be serialized to JSON. In this case we don't need to but we could use [Jackson](https://github.com/FasterXML/jackson) annotations if we wanted to customize the JSON serialization.
 * We do a simple transformation between `MyEvent` and `MyEventPayload` just as an example.
 * Every time we emit a `MyEventPayload` through the `Flux`, Spring Cloud Stream will publish it to Kafka.
 
-### 3) Finally, we create an instance of `MyStreamEventProducer` naming it `my-producer` to link it to the function definition:
+### 3) Finally, we configure the beans needed to link `my-producer` function definition:
 ```kotlin
 @Configuration
 class MyConfiguration { 
+  @Bean
+  fun myStreamEventProducer() = MyStreamEventProducer()
+  
   @Bean("my-producer")
-  fun myStreamEventProducer(): MyEventProducer {
-    return MyStreamEventProducer()
-  }
+  fun myStreamEventProducerFunction(producer: MyStreamEventProducer): () -> Flux<Message<MyEventPayload>> =
+    producer::get
 }
 ```
+* We create a `MyStreamEventProducer` that will be injected wherever a `MyEventProducer` is needed.
+* We create a lambda returning a `Flux<Message<MyEventPayload>>` that will be linked to the `my-producer` function, implemented by calling `myStreamEventProducer.get()` method.
+* We do not merge both beans in one to avoid issues with `KotlinLambdaToFunctionAutoConfiguration`.
 
 ### 4) For testing we start a Kafka container using [Testcontainers](https://www.testcontainers.org/):
 ```kotlin
@@ -143,7 +148,7 @@ Our final goal is to consume messages from a Kafka topic.
 
 From the point of view of the application we want an interface `MyEventConsumer` to be called every time an event is consumed from a generic messaging system. These events will be of type `MyEvent` like in the producer example:
 ```kotlin
-class MyEvent(val text: String)
+data class MyEvent(val text: String)
 
 interface MyEventConsumer {
   fun consume(event: MyEvent)
@@ -152,7 +157,7 @@ interface MyEventConsumer {
 
 Then we follow these steps:
 
-### 1) We declare the binding `my-consumer` in application.yml:
+### 1) We configure the binding `my-consumer` in application.yml declaring it as a function:
 ```yaml
 spring:
   cloud:
@@ -171,10 +176,10 @@ spring:
 * We configure a `group` because we want the application to consume from Kafka identifiying itself as a consumer group so if there were to be more than one instance of the application every message will be delivered to only one of the instances. 
 * As stated in [functional binding names](https://docs.spring.io/spring-cloud-stream/docs/current/reference/html/spring-cloud-stream.html#_functional_binding_names): `my-consumer` is the function name, `in` is for input bindings and `0` is the index we have to use if we have a single function.
 
-### 2) We create the same class `MyStreamEventConsumer` implementing `Consumer<MyEventPayload>` to fulfill the interface required by Spring Cloud Stream:
+### 2) We create `MyStreamEventConsumer` to fulfill the interface required by Spring Cloud Stream:
 ```kotlin
-class MyStreamEventConsumer(private val consumer: MyEventConsumer) : Consumer<MyEventPayload> {
-  override fun accept(payload: MyEventPayload) {
+class MyStreamEventConsumer(private val consumer: MyEventConsumer) : (MyEventPayload) -> Unit {
+  override fun invoke(payload: MyEventPayload) {
     consumer.consume(fromPayload(payload))
   }
 
@@ -183,28 +188,26 @@ class MyStreamEventConsumer(private val consumer: MyEventConsumer) : Consumer<My
   }
 }
 ```
-* Every time a new message is received in the Kafka topic, its payload will be deserialized to a `MyEventPayload` (applying [Jackson](https://github.com/FasterXML/jackson) annotations) and the `consume` method will we called.
+* Every time a new message is received in the Kafka topic, its payload will be deserialized to a `MyEventPayload` and the `invoke` method will we called.
 * Then the only thing we have to do is to tranform the `MyEventPayload` to a `MyEvent` and callback the generic `MyEventConsumer`.
 
-### 3) Finally, we create an instance of `MyStreamEventConsumer` naming it `my-consumer` to link it to the function definition:
+### 3) Finally, we configure the beans needed to link `my-consumer` function definition:
 ```kotlin
 @Configuration
 class MyConfiguration {
-  @Bean("my-consumer")
-  fun myStreamEventConsumer(consumer: MyEventConsumer): MyStreamEventConsumer {
-    return MyStreamEventConsumer(consumer)
-  }
-  
   @Bean
-  fun myEventConsumer(): MyEventConsumer {
-    return object : MyEventConsumer {
-      override fun consume(event: MyEvent) {
-        println("Received ${event.text}")
-      }
+  fun myEventConsumer() = object : MyEventConsumer {
+    override fun consume(event: MyEvent) {
+      println("Received ${event.text}")
     }
   }
+
+  @Bean("my-consumer")
+  fun myStreamEventConsumerFunction(consumer: MyEventConsumer): (MyEventPayload) -> Unit =
+    MyStreamEventConsumer(consumer)
 }
 ```
+* We create a lambda receiving a `MyEventPayload` that will be linked to the `my-consumer` function, implemented by a `MyStreamEventConsumer`.
 * We create a simple implementation of `MyEventConsumer` that justs prints the event.
 
 ### 4) For testing we start a Kafka container using [Testcontainers](https://www.testcontainers.org/):
@@ -242,14 +245,14 @@ When a message is sent to a topic, Kafka chooses randomly the destination partit
 
 This is important on the consumer side, because **chronological order of messages is only guaranteed within the same partition**, so if we need to consume some messages in the order they were produced, we should use the same key for all of them (i.e. for messages of a *user*, we use the *user* id as the message key).
 
-To specify the message key in `MyStreamEventProducer` we can produce `Message<MyEventPayload>` instead of `MyEventPayload` and inform the `KafkaHeaders.MESSAGE_KEY` header:
+To specify the message key in `MyStreamEventProducer` we can produce `Message<MyEventPayload>` instead of `MyEventPayload` and inform the `KafkaHeaders.KEY` header:
 ```kotlin
 class MyStreamEventProducer : Supplier<Flux<Message<MyEventPayload>>>, MyEventProducer {
   // ...
   override fun produce(event: MyEvent) {
     val message = MessageBuilder
       .withPayload(MyEventPayload(event.text, event.text.length))
-      .setHeader(KafkaHeaders.MESSAGE_KEY, "key-${event.text.length}")
+      .setHeader(KafkaHeaders.KEY, "key-${event.text.length}")
       .build()
     sink.emitNext(message, FAIL_FAST)
   }
diff --git a/build.gradle.kts b/build.gradle.kts
index 1bdcba8..6e91f77 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -3,21 +3,22 @@ import org.gradle.api.tasks.testing.logging.TestLogEvent.*
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-  id("org.springframework.boot") version "2.6.2"
-  id("io.spring.dependency-management") version "1.0.11.RELEASE"
-  kotlin("jvm") version "1.6.10"
-  kotlin("plugin.spring") version "1.6.10"
+  id("org.springframework.boot") version "3.1.5"
+  id("io.spring.dependency-management") version "1.1.3"
+  kotlin("jvm") version "1.9.20"
+  kotlin("plugin.spring") version "1.9.20"
 }
 
 group = "com.rogervinas"
 version = "0.0.1-SNAPSHOT"
-java.sourceCompatibility = JavaVersion.VERSION_11
+java.sourceCompatibility = JavaVersion.VERSION_21
+java.targetCompatibility = JavaVersion.VERSION_21
 
 repositories {
 	mavenCentral()
 }
 
-extra["springCloudVersion"] = "2021.0.0"
+extra["springCloudVersion"] = "2022.0.4"
 
 dependencies {
 	implementation("org.springframework.boot:spring-boot-starter-web")
@@ -43,7 +44,7 @@ dependencyManagement {
 tasks.withType<KotlinCompile> {
 	kotlinOptions {
 		freeCompilerArgs = listOf("-Xjsr305=strict")
-		jvmTarget = "11"
+		jvmTarget = "21"
 	}
 }
 
@@ -55,5 +56,5 @@ tasks.withType<Test> {
     showExceptions = true
     showCauses = true
     showStackTraces = true
-  }	  
+  }
 }
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index e708b1c..033e24c 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 2e6e589..3fa8f86 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index 4f906e0..fcb6fca 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,67 +17,98 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -87,9 +118,9 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -98,88 +129,120 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
 fi
 
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
     # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
         fi
-        i=`expr $i + 1`
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
     done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
-    esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index 107acd3..6689b85 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -1,89 +1,92 @@
-@rem
-@rem Copyright 2015 the original author or authors.
-@rem
-@rem Licensed under the Apache License, Version 2.0 (the "License");
-@rem you may not use this file except in compliance with the License.
-@rem You may obtain a copy of the License at
-@rem
-@rem      https://www.apache.org/licenses/LICENSE-2.0
-@rem
-@rem Unless required by applicable law or agreed to in writing, software
-@rem distributed under the License is distributed on an "AS IS" BASIS,
-@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-@rem See the License for the specific language governing permissions and
-@rem limitations under the License.
-@rem
-
-@if "%DEBUG%" == "" @echo off
-@rem ##########################################################################
-@rem
-@rem  Gradle startup script for Windows
-@rem
-@rem ##########################################################################
-
-@rem Set local scope for the variables with windows NT shell
-if "%OS%"=="Windows_NT" setlocal
-
-set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
-set APP_BASE_NAME=%~n0
-set APP_HOME=%DIRNAME%
-
-@rem Resolve any "." and ".." in APP_HOME to make it shorter.
-for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
-
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
-
-@rem Find java.exe
-if defined JAVA_HOME goto findJavaFromJavaHome
-
-set JAVA_EXE=java.exe
-%JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
-
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:findJavaFromJavaHome
-set JAVA_HOME=%JAVA_HOME:"=%
-set JAVA_EXE=%JAVA_HOME%/bin/java.exe
-
-if exist "%JAVA_EXE%" goto execute
-
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:execute
-@rem Setup the command line
-
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
-
-
-@rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
-
-:end
-@rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
-
-:fail
-rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
-rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
-
-:mainEnd
-if "%OS%"=="Windows_NT" endlocal
-
-:omega
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/src/main/kotlin/com/rogervinas/stream/domain/MyEvent.kt b/src/main/kotlin/com/rogervinas/stream/domain/MyEvent.kt
index 6c3e73e..f6feb45 100644
--- a/src/main/kotlin/com/rogervinas/stream/domain/MyEvent.kt
+++ b/src/main/kotlin/com/rogervinas/stream/domain/MyEvent.kt
@@ -1,3 +1,3 @@
 package com.rogervinas.stream.domain
 
-class MyEvent(val text: String)
+data class MyEvent(val text: String)
diff --git a/src/main/kotlin/com/rogervinas/stream/functional/MyConfiguration.kt b/src/main/kotlin/com/rogervinas/stream/functional/MyConfiguration.kt
index 1d2f1ac..85778bf 100644
--- a/src/main/kotlin/com/rogervinas/stream/functional/MyConfiguration.kt
+++ b/src/main/kotlin/com/rogervinas/stream/functional/MyConfiguration.kt
@@ -2,29 +2,30 @@ package com.rogervinas.stream.functional
 
 import com.rogervinas.stream.domain.MyEvent
 import com.rogervinas.stream.domain.MyEventConsumer
-import com.rogervinas.stream.domain.MyEventProducer
+import com.rogervinas.stream.shared.MyEventPayload
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
+import org.springframework.messaging.Message
+import reactor.core.publisher.Flux
 
 @Configuration
 class MyConfiguration {
 
-  @Bean("my-producer")
-  fun myStreamEventProducer(): MyEventProducer {
-    return MyStreamEventProducer()
+  @Bean
+  fun myEventConsumer() = object : MyEventConsumer {
+    override fun consume(event: MyEvent) {
+      println("Received ${event.text}")
+    }
   }
 
   @Bean("my-consumer")
-  fun myStreamEventConsumer(consumer: MyEventConsumer): MyStreamEventConsumer {
-    return MyStreamEventConsumer(consumer)
-  }
+  fun myStreamEventConsumerFunction(consumer: MyEventConsumer): (MyEventPayload) -> Unit =
+    MyStreamEventConsumer(consumer)
 
   @Bean
-  fun myEventConsumer(): MyEventConsumer {
-    return object : MyEventConsumer {
-      override fun consume(event: MyEvent) {
-        println("Received ${event.text}")
-      }
-    }
-  }
+  fun myStreamEventProducer() = MyStreamEventProducer()
+
+  @Bean("my-producer")
+  fun myStreamEventProducerFunction(producer: MyStreamEventProducer): () -> Flux<Message<MyEventPayload>> =
+    producer::get
 }
diff --git a/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventConsumer.kt b/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventConsumer.kt
index 8952cd9..874802a 100644
--- a/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventConsumer.kt
+++ b/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventConsumer.kt
@@ -3,11 +3,10 @@ package com.rogervinas.stream.functional
 import com.rogervinas.stream.domain.MyEvent
 import com.rogervinas.stream.domain.MyEventConsumer
 import com.rogervinas.stream.shared.MyEventPayload
-import java.util.function.Consumer
 
-class MyStreamEventConsumer(private val consumer: MyEventConsumer) : Consumer<MyEventPayload> {
+class MyStreamEventConsumer(private val consumer: MyEventConsumer) : (MyEventPayload) -> Unit {
 
-  override fun accept(payload: MyEventPayload) {
+  override fun invoke(payload: MyEventPayload) {
     consumer.consume(fromPayload(payload))
   }
 
diff --git a/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt b/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt
index 7417afc..ec5de3f 100644
--- a/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt
+++ b/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt
@@ -13,12 +13,12 @@ import java.util.function.Supplier
 
 class MyStreamEventProducer : Supplier<Flux<Message<MyEventPayload>>>, MyEventProducer {
 
-  val sink = Sinks.many().unicast().onBackpressureBuffer<Message<MyEventPayload>>()
+  private val sink = Sinks.many().unicast().onBackpressureBuffer<Message<MyEventPayload>>()
 
   override fun produce(event: MyEvent) {
     val message = MessageBuilder
       .withPayload(toPayload(event))
-      .setHeader(KafkaHeaders.MESSAGE_KEY, toKey(event))
+      .setHeader(KafkaHeaders.KEY, toKey(event))
       .build()
     sink.emitNext(message, FAIL_FAST)
   }
diff --git a/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt b/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt
index 7a33949..8f270b6 100644
--- a/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt
+++ b/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt
@@ -1,43 +1,29 @@
 package com.rogervinas.stream.shared
 
+import jakarta.annotation.PostConstruct
+import jakarta.annotation.PreDestroy
 import org.springframework.context.annotation.Profile
 import org.springframework.stereotype.Component
-import org.testcontainers.containers.DockerComposeContainer
-import org.testcontainers.containers.wait.strategy.HostPortWaitStrategy
+import org.testcontainers.containers.ComposeContainer
 import org.testcontainers.containers.wait.strategy.Wait.forLogMessage
-import org.testcontainers.containers.wait.strategy.WaitAllStrategy
-import org.testcontainers.containers.wait.strategy.WaitAllStrategy.Mode.WITH_INDIVIDUAL_TIMEOUTS_ONLY
 import java.io.File
-import java.util.stream.Collectors
-import javax.annotation.PostConstruct
-import javax.annotation.PreDestroy
 
 @Component
 @Profile("docker-compose")
 class MyContainers {
 
-  private val KAFKA = "kafka"
-  private val KAFKA_PORT = 9094
+  companion object {
+    private const val KAFKA = "kafka"
+    private const val KAFKA_PORT = 9094
 
-  private val ZOOKEEPER = "zookeeper"
-  private val ZOOKEEPER_PORT = 2181
-
-  private val container = DockerComposeContainer<Nothing>(File("docker-compose.yml"))
-    .apply { withLocalCompose(true) }
-    .apply {
-      withExposedService(KAFKA, KAFKA_PORT, WaitAllStrategy(WITH_INDIVIDUAL_TIMEOUTS_ONLY)
-        .apply { withStrategy(forListeningPortFixDockerDesktop322()) }
-        .apply { withStrategy(forLogMessage(".*creating topics.*", 1)) }
-      )
-    }
-    .apply {
-      withExposedService(ZOOKEEPER, ZOOKEEPER_PORT, WaitAllStrategy(WITH_INDIVIDUAL_TIMEOUTS_ONLY)
-        .apply { withStrategy(forListeningPortFixDockerDesktop322()) }
-        .apply { withStrategy(forLogMessage(".*binding to port.*", 1)) }
-      )
-    }
+    private const val ZOOKEEPER = "zookeeper"
+    private const val ZOOKEEPER_PORT = 2181
+  }
 
-  private fun forListeningPortFixDockerDesktop322() = HostPortWaitStrategyFixDockerDesktop322()
+  private val container = ComposeContainer(File("docker-compose.yml"))
+    .withLocalCompose(true)
+    .withExposedService(KAFKA, KAFKA_PORT, forLogMessage(".*creating topics.*", 1))
+    .withExposedService(ZOOKEEPER, ZOOKEEPER_PORT, forLogMessage(".*binding to port.*", 1))
 
   @PostConstruct
   fun start() = container.start()
@@ -45,11 +31,3 @@ class MyContainers {
   @PreDestroy
   fun stop() = container.stop()
 }
-
-class HostPortWaitStrategyFixDockerDesktop322 : HostPortWaitStrategy() {
-  override fun getLivenessCheckPorts(): MutableSet<Int> {
-    return super.getLivenessCheckPorts().stream()
-      .filter { port -> port > 0 }
-      .collect(Collectors.toSet())
-  }
-}
diff --git a/src/main/kotlin/com/rogervinas/stream/shared/MyEventPayload.kt b/src/main/kotlin/com/rogervinas/stream/shared/MyEventPayload.kt
index 0c47977..a27972f 100644
--- a/src/main/kotlin/com/rogervinas/stream/shared/MyEventPayload.kt
+++ b/src/main/kotlin/com/rogervinas/stream/shared/MyEventPayload.kt
@@ -1,9 +1,6 @@
 package com.rogervinas.stream.shared
 
-import com.fasterxml.jackson.annotation.JsonCreator
-import com.fasterxml.jackson.annotation.JsonProperty
-
-class MyEventPayload @JsonCreator constructor(
-  @JsonProperty("string") val string: String,
-  @JsonProperty("number") val number: Int
+data class MyEventPayload(
+  val string: String,
+  val number: Int
 )
diff --git a/src/test/kotlin/com/rogervinas/stream/MyApplicationShould.kt b/src/test/kotlin/com/rogervinas/stream/MyApplicationShould.kt
index addf41c..eef57fb 100644
--- a/src/test/kotlin/com/rogervinas/stream/MyApplicationShould.kt
+++ b/src/test/kotlin/com/rogervinas/stream/MyApplicationShould.kt
@@ -29,11 +29,13 @@ import java.util.function.Consumer
 @ActiveProfiles("docker-compose")
 class MyApplicationShould {
 
-  val TOPIC = "my.topic"
-  val TOPIC_DLQ = "my.topic.errors"
+  companion object {
+    private const val TOPIC = "my.topic"
+    private const val TOPIC_DLQ = "my.topic.errors"
 
-  val TEN_SECONDS = Duration.ofSeconds(10)
-  val FIVE = 5
+    private val TEN_SECONDS = Duration.ofSeconds(10)
+    private const val FIVE = 5
+  }
 
   @Autowired
   lateinit var env: Environment
diff --git a/src/test/kotlin/com/rogervinas/stream/MyKafkaConsumerHelper.kt b/src/test/kotlin/com/rogervinas/stream/MyKafkaConsumerHelper.kt
index 99edba6..0b5b136 100644
--- a/src/test/kotlin/com/rogervinas/stream/MyKafkaConsumerHelper.kt
+++ b/src/test/kotlin/com/rogervinas/stream/MyKafkaConsumerHelper.kt
@@ -43,7 +43,7 @@ class MyKafkaConsumerHelper(bootstrapServers: String, topic: String) {
     config.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers)
     config.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer::class.java.name)
     config.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer::class.java.name)
-    config.setProperty(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, OffsetResetStrategy.EARLIEST.name.toLowerCase())
+    config.setProperty(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, OffsetResetStrategy.EARLIEST.name.lowercase())
     return config
   }
 }
diff --git a/src/test/kotlin/com/rogervinas/stream/MyKafkaProducerHelper.kt b/src/test/kotlin/com/rogervinas/stream/MyKafkaProducerHelper.kt
index ffa50bb..6baf6a7 100644
--- a/src/test/kotlin/com/rogervinas/stream/MyKafkaProducerHelper.kt
+++ b/src/test/kotlin/com/rogervinas/stream/MyKafkaProducerHelper.kt
@@ -5,7 +5,7 @@ import org.apache.kafka.clients.producer.Producer
 import org.apache.kafka.clients.producer.ProducerConfig
 import org.apache.kafka.clients.producer.ProducerRecord
 import org.apache.kafka.common.serialization.StringSerializer
-import java.util.*
+import java.util.Properties
 
 class MyKafkaProducerHelper(bootstrapServers: String) {